As airframe become more and more complex, and are called upon to perform increasingly stre~sful maneuvers, autopilots must be robust enough to adequately stabilize the airframe in the highly non-linear, strongly cross-coupled environments. Classic autopilot design can achieve stability throughout he flight envelope, but generally lack robustness for design and environmental ehange.~. Guidance a...

Since the introduction of large jet-powered transport aircraft, the majority of these vehicles have been designed by placing thrust-generating engines either under the wings or on the fuselage to minimize aerodynamic interactions on the vehicle operation. However, advances in computational and experimental tools along with new technologies in materials, structures, and aircraft controls, etc. a...

ABSTRACT Reported herein is an overview of the research being conducted within the Materials Division at NASA Langley Research Center on the development of smart material technologies for advanced airframe systems. The research is a part of the Aircraft Morphing Program which is a new six-year research program to develop smart components for self-adaptive airframe systems. The fundamental areas...

A model for the dynamics of a four rotor vertical take-off and landing (VTOL) vehicle known as an X4-flyer is proposed. The model incorporates the airframe and motor dynamics as well as aerodynamic and gyroscopic effects due to the rotors for quasi-stationary flight conditions. A novel control strategy is proposed for configuration stabilization of quasi-stationary flight conditions. The approa...

Introduction: Astrobiology is by nature a system-level science, meaning that it is concerned with complex , multidisciplinary, multi-phenomena behaviors of large physical and biological systems. Due to the breadth of the undertakings in astrobiological inquiry, researchers in the field must rely heavily on information technology to consolidate and represent knowledge and data from across many d...

In this combined experimental and numerical study, the propeller–airframe aerodynamic interaction is characterized for an aircraft configuration with propellers mounted to horizontal tailplane. The contributions of propeller airframe overall loading are distinguished in analyses by using a combination external balance internal load cell data. Validated computational fluid dynamics simulations t...

The NASA goal of reducing external aircraft noise by 10 dB in the near-term presents the acoustics community with an enormous challenge. This report identifies technologies with the greatest potential to reduce airframe noise. Acoustic and aerodynamic effects will be discussed, along with the likelihood of industry accepting and implementing the different technologies. We investigate the lower ...